As is known, bottles containing oily or soapy liquids are inevitably slippery after a time; therefore they can be difficult to grasp and thus they are often formed with particular shapes that make handgrip more secure.
For example, bottles provided with handles or shaped with indented sides are known, that allow an efficient grasp; reference is made to bottles shown in U.S. Pat. Nos. 4,846,359 and D491,067. Nevertheless these shape features have a strong impact on the appearance of the body of the bottle; this impact sometimes is not acceptable.
For example it can be understood that bottles provided with handgrip work in a good way for soap, detersives and the like, but they do not fit with products which are more valuable and expensive such as olive oil, for which the aesthetic aspect of the packaging is important.
Also for this reason detersives are usually contained in plastic bottles that can be produced at a low cost and in a relatively easy way (for moulding and the like) with different shapes, while olive oil is mostly sold in glass bottles which are more expensive and difficult to manufacture, particularly in the case of complex shapes as those with handgrips and the like.